KOFOID AND RIGDEN: SCHIZOGONY IN GONYAULAX. 345 



the longitudinal furrow. The posterior intercalary, 1p, is extraordi- 

 narily wide for this plate, and the antapical is revealed only along its 

 posterior margin (1"", Plate 1, fig. 2). The possibility of several ant- 

 apicals as in Goniodoma must be kept open in view of the incomplete- 

 ness of the thecae in this region. If present a different generic 

 assignment will be necessary. 



The plates of the ventral area (see fig. B, v. a.) are not all present 

 and it is difficult to distinguish this region in the middle of the chain, 

 for example, from the ventral apical region of the next posterior mem- 

 ber of the chain. The interpretation in the anterior part of the chain 

 of the plates of the epitheca is so conclusive that the analysis in the 

 less sharply differentiated, more central members (Plate 2, fig. 4) is 

 however, made possible. Five plates of the ventral area (v. a.) can 

 be distinguished. These are the anterior plates (ant. pi.) opposite 

 the end of the transverse furrow, with a slight anterior lobe indenting 

 the epitheca, and posterior to this two pairs of intermediate plates 

 (int. pis.) which abut posteriorly directly against the mid ventral 

 apical, 1/ and the plate conditionally interpreted as the anterior inter- 

 calary, l a of the next posterior schizont. The plate immediately 

 adjacent to the proximal end of the girdle marks the region of the 

 flagellar pore (fl. po.). 



The surface of the theca is absolutely smooth, without trace of 

 markings or pores and the wall is a delicate hyaline membrane whose 

 only structural features are the barely outlined sutures which in the 

 distal members of the chain are not always demonstrable. 



The same pattern of skeleton is exhibited throughout all members of 

 the chain, the only differences being those resulting from variations 

 in differentiation of sutures and in size and extent of union of adjacent 

 thecae which in the three larger members results in considerable 

 modification in size, proportions or expanse of the plates. The thecal 

 formation has not progressed equally in all portions of the chain. 

 In the central members the sutures are more evident and those of 

 the ventral area can be determined. Distally in the four members 

 at either end the sutures are exceedingly faint or even not demon- 

 strable under the best conditions of magnification and illumination. 



The cell contents (Plate 2, fig. 3) form an unbroken axial mass of 

 cytoplasm which is nowhere constricted between the schizonts to a 

 total depth on the two sides exceeding one third of the equatorial 

 diameter of the adjacent cell bodies. In fact in the central part of 

 the chain the constrictions are even less developed. The plasma is 

 densely granular and upon treatment with iodine, clusters of small 



